Solution is an aftermarket regulator.

 

Yup I got an Aeromotive one here next to me, just waiting for some free time to put it in.

 

I think a return style flex fuel regulator will get the job done, or at least that's the route I'm going when the turbo goes on this truck. I'm having zero issues right now with a stock 99 rail..24lb injectors and a 400 intank with hotwire kit. I'm seeing 65lb fuel pressure at idle and drops with vacuume.

 

Idle pressure should be low 50's, and 58 with the vac line disconnected, correct? This is what I was getting stock and with the 255. If you're seeing 65psi then I would think that you do have an issue. That's what I was seeing as well with the 400. But if yours does vary with vac then I don't know.

Is the flex fuel regulator a direct replacement for a stock 99-02 regulator? Link or part number? That would certainly be the cheaper and easier solution.

 

No you have to have the whole rail. The return hole is about twice as big as the non flex rail.